Remove duplication between page merge functions

ocrmypdf/pipeline.py

@@ -900,29 +900,42 @@ def skip_page(
     re_symlink(input_file, output_file, log)
 
 
+def _merge_pages_common(
+        input_files_groups,
+        output_file,
+        log,
+        context):
+    """Determine ordered list of PDF pages to merge. Returns PDF from which
+    metadata should be drawn if present (for qpdf)."""
+
+    input_files = list(f for f in flatten_groups(input_files_groups)
+                       if not f.endswith('.txt'))
+    metadata_file = next(
+        (ii for ii in input_files if ii.endswith('.repaired.pdf')), None)
+    input_files.remove(metadata_file)
+
+    def input_file_order(s):
+        '''Sort order: All rendered pages followed
+        by their debug page.'''
+        key = page_number(s) * 10
+        if 'debug' in os.path.basename(s):
+            key += 1
+        return key
+
+    pdf_pages = sorted(input_files, key=input_file_order)
+    log.debug("Final pages: " + "\n".join(pdf_pages))
+
+    return pdf_pages, metadata_file
+
+
 def merge_pages_ghostscript(
         input_files_groups,
         output_file,
         log,
         context):
     options = context.get_options()
-    def input_file_order(s):
-        '''Sort order: All rendered pages followed
-        by their debug page, if any, followed by Postscript stub.
-        Ghostscript documentation has the Postscript stub at the
-        beginning, but it works at the end and also gets document info
-        right that way.'''
-        if s.endswith('.ps'):
-            return 99999999
-        key = page_number(s) * 10
-        if 'debug' in os.path.basename(s):
-            key += 1
-        return key
-
-    input_files = (f for f in flatten_groups(input_files_groups)
-                   if not f.endswith('.txt'))
-    pdf_pages = sorted(input_files, key=input_file_order)
-    log.debug("Final pages: " + "\n".join(pdf_pages))
+    pdf_pages, _ = _merge_pages_common(
+        input_files_groups, output_file, log, context)
     input_pdfinfo = context.get_pdfinfo()
     ghostscript.generate_pdfa(
         pdf_version=input_pdfinfo.min_version,
@@ -940,23 +953,8 @@ def merge_pages_qpdf(
         log,
         context):
     options = context.get_options()
-
-    input_files = list(f for f in flatten_groups(input_files_groups)
-                       if not f.endswith('.txt'))
-    metadata_file = next(
-        (ii for ii in input_files if ii.endswith('.repaired.pdf')))
-    input_files.remove(metadata_file)
-
-    def input_file_order(s):
-        '''Sort order: All rendered pages followed
-        by their debug page.'''
-        key = page_number(s) * 10
-        if 'debug' in os.path.basename(s):
-            key += 1
-        return key
-
-    pdf_pages = sorted(input_files, key=input_file_order)
-    log.debug("Final pages: " + "\n".join(pdf_pages))
+    pdf_pages, metadata_file = _merge_pages_common(
+        input_files_groups, output_file, log, context)
 
     reader_metadata = pypdf.PdfFileReader(metadata_file)
     pdfmark = get_pdfmark(reader_metadata, options)
@@ -965,7 +963,8 @@ def merge_pages_qpdf(
     first_page = pypdf.PdfFileReader(pdf_pages[0])
 
     writer = pypdf.PdfFileWriter()
-    writer._header = b'%PDF-' + _pdf_guess_version(pdf_pages[0])  # copy version from source
+    # copy version from source
+    writer._header = b'%PDF-' + _pdf_guess_version(pdf_pages[0])
     writer.appendPagesFromReader(first_page)
     writer.addMetadata(pdfmark)
     writer_file = pdf_pages[0].replace('.pdf', '.metadata.pdf')